Many ranging systems use a single frequency, continuous wave for ranging. Such systems measure the phase of the received reflected wave with respect to the transmitted wave to measure the distance of the object in the scene. The phase of the returning wave “wraps” at 2π, thereby leading to a distance ambiguity. A common technique to extend the range is to use another frequency of operation and extend the unambiguous range to the Least Common Multiple (LCM) of the two ranges. However, the calculations involved are complex and requiring significant Integrated Circuit (IC) silicon area and/or time to compute the de-aliased (actual) distance.
In practical scenarios, since the measurements from the two frequencies will not match perfectly, a search for the best match is typically performed in the distance domain after converting the plurality of acquired phases to distances. Some existing methods use a search algorithm to find the closest match for the two frequencies to find the bin (set) in which the object lies. The search takes a O(n) time where, n is proportional to the range extension (i.e. extension beyond wrap of the phase of the measuring frequencies) if implemented on a serial processor or takes O(n) silicon area if implemented in a parallel processor. Some existing methods use a divider to compute with O(1) time complexity, but dividers are expensive in terms of IC silicon area and/or processor time.